12V or 24V for a 2000W inverter with induction cooktop

HarryN

New Member
Not all induction cooktops are created equal. European models have power factor correcting power supplies, U.S. models generally do not.

Since U.S. residential grid usage has no regulations on power factor, many manufacturers cut costs by just using simple rectifier-filter cap to convert incoming single phase AC to DC to run induction drive inverter circuitry. For residential usage, U.S. grid charges are based on true power so there is no incentive to have good power factor appliances.

Same goes for variable compressor speed inverter-refrig's. My expensive variable speed compressor Samsung 28 cu-ft has very crappy power factor of 0.6. The European Samsung model does have PF correction.

Running poor PF loads on inverters degrades inverter efficiency so consumes more battery power. The lower the PF of load, the higher the peak inverter current. Inverter losses are proportional to current through MOSFET switches and transformer.

Since U.S. market for mini-split inverter-air conditioners is small, and Europe/other countries that do use most of mini-splits built have PF regulations, most of the mini-splits even in U.S., do have PF correcting power supplies.

The power factor aspect depends on the grid supplier. In CA, the original meters did not measure PF, but with the smart meters they do and we are charged more for it even in a residence.

Some inverters are better at dealing with this PF aspect - some really struggle.
 

filippomasoni

New Member
But you can source 24V so much easier in Europe. As long as you buy quality, I don't see the problem.

Everything can handle more watts and the system will run easier, probably last longer due to less heat.
Great! I'll go with the 24V then and order the 8 280ah cells in the next few days.
 
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mininut2

New Member
This is my first post and I am doing something similar to you, which I will do a post on soon. You said that it takes 3 months to get gear delivered to Europe from China. I have just received my 8 x 280a cells from RJ Energy. Ordered on 17/06/21, got a tracking number on 24/06/21 and received my shipment on 26/07/21. I am in Australia
Rick
 

filippomasoni

New Member
Unable to refill LPG bottles in the EU?
Stay with gas and upgrade the 12v truck system you already have to power less energy hogging appliances.
I'm building a new truck camper with the purpose of traveling around the world. I know LPG is common in Europe but if I want to go with the fiberglass lighter containers those are not as common and I still have to search for it everytime, which means I need to have 2 for redundancy and those takes a lot of space and weight. Also traveling around and sleeping close it LPG everyday is probably not the safest thing.
On the other hand I did consider saving money and go with that at first and upgrade when needed. If I don't need electricity to cook, half the battery capacity will be enough and a 300W inverter will be more than enough as I will need it only for a PC monitor that draws 25W. When the time comes though I'll have to buy a lot of new stuff though, as everything changes to 24V which means I'll have to spend a lot of extra money
 

filippomasoni

New Member
This is my first post and I am doing something similar to you, which I will do a post on soon. You said that it takes 3 months to get gear delivered to Europe from China. I have just received my 8 x 280a cells from RJ Energy. Ordered on 17/06/21, got a tracking number on 24/06/21 and received my shipment on 26/07/21. I am in Australia
Rick
Great, I'll follow your post then. That's very quick. Can you share the link of the supplier? I was looking at the aliexpress ones from these suppliers: https://www.mobile-solarpower.com/raw-lifepo4-deals-page.html and they all take about 3 months.
 

mininut2

New Member
Alice Gan <sale25@lithiumbattery-rj.com. This is the lady that I dealt with. The 8 cells cost me $1175.00USD delivered to my door. I had to pay GST (Tax) and customs charges in Oz. That also included busbars. The studs are laser welded and are a bit short (about 16-18mm, I think. I unpacked them and then re-packed them so can't check the length)
Rick
 

filippomasoni

New Member
Not all induction cooktops are created equal. European models have power factor correcting power supplies, U.S. models generally do not.

Since U.S. residential grid usage has no regulations on power factor, many manufacturers cut costs by just using simple rectifier-filter cap to convert incoming single phase AC to DC to run induction drive inverter circuitry. For residential usage, U.S. grid charges are based on true power so there is no incentive to have good power factor appliances.

Same goes for variable compressor speed inverter-refrig's. My expensive variable speed compressor Samsung 28 cu-ft has very crappy power factor of 0.6. The European Samsung model does have PF correction.

Running poor PF loads on inverters degrades inverter efficiency so consumes more battery power. The lower the PF of load, the higher the peak inverter current. Inverter losses are proportional to current through MOSFET switches and transformer.

Since U.S. market for mini-split inverter-air conditioners is small, and Europe/other countries that do use most of mini-splits built have PF regulations, most of the mini-splits even in U.S., do have PF correcting power supplies.
I didn't quite understand and I'm very interested in this. I know there are a lot of cheap induction cooktops but I want to get a good one, so how can I check for this?

What's a power factor correcting power supplier?

I'm not sure if you're talking about this, but most small households here in Italy have a maximum draw of 3kW, the upgrade to 4.5 has monthly bill costs. A peak 3kW is very easy to reach of course, so some of the Induction cooktops have features to limit the maximum draw, especially on the big 4 zones that go up to 7kW and more. I don't think the limit is applied as an average (having peak and then off) but it should limit the peak otherwise it will trigger the 3kW breaker.

Also, you mention AC to DC, does that mean induction actually works with DC? Does a DC induction cooktop exist? I tried searching but didn't find anything. That would be perfect without having to use the inverter for that big load, and also save a lot of energy due to conversion loss.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
I would like to gently remind folks, you are tossing around numbers without realizing...
The general unwritten rule is to not draw more than 250A from a battery bank (excepting surge handling).
12V@250A=3000W (25A AC),
24V@250A=6000W (50A AC),
48V@250A=12,000W (100A AC)
 

filippomasoni

New Member
I would like to gently remind folks, you are tossing around numbers without realizing...
The general unwritten rule is to not draw more than 250A from a battery bank (excepting surge handling).
12V@250A=3000W (25A AC),
24V@250A=6000W (50A AC),
48V@250A=12,000W (100A AC)
Yes, I know that. Even if I would be building a 12V system I wouldn't draw more than 2000W from it. Before when I thought I would need 3600W for the induction I was only considering 24V for this exact reason. But yes, it's always a good reminder.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Yes, I know that. Even if I would be building a 12V system I wouldn't draw more than 2000W from it. Before when I thought I would need 3600W for the induction I was only considering 24V for this exact reason. But yes, it's always a good reminder.
BUT that is the CATCH many fall into. People ALWAYS underestimate their use and NEVER consider the times when they WILL use more power than they had thought & planned for. Understand that roughly 50% of people end up Upgrading in < 1 year because of it... and we all know how that is something that makes people angry because they have to spend more & redo things.

I used to always tell people if you "think you need 3000W you more than likely need 4000W so plan to build One Step above your estimate, then people would get angry, and later if/when they had to upgrade, I got crapped on, so I stopped telling folks in general. People hate to hear things they don't want to hear, even when it is in their best interest (and their financial happiness, nothing worse than having an angry spouse because you goofed and wasted hard-earned cash).

BTW, Real world examples for you to think about.
Panasonic 1200W Inverter Microwave (120VAC) pulls 75A from 24V Bank, which is 150A off 12V, while running.
Oster Coffee Maker (no warmer, thermal carafe) pulls 50A from 24V for 6 minutes while brewing.
Couple of common things that everyone can relate to.
 

filippomasoni

New Member
BUT that is the CATCH many fall into. People ALWAYS underestimate their use and NEVER consider the times when they WILL use more power than they had thought & planned for. Understand that roughly 50% of people end up Upgrading in < 1 year because of it... and we all know how that is something that makes people angry because they have to spend more & redo things.

I used to always tell people if you "think you need 3000W you more than likely need 4000W so plan to build One Step above your estimate, then people would get angry, and later if/when they had to upgrade, I got crapped on, so I stopped telling folks in general. People hate to hear things they don't want to hear, even when it is in their best interest (and their financial happiness, nothing worse than having an angry spouse because you goofed and wasted hard-earned cash).

You are so right! 😅

I started by saying I'll build a basic 12V system and cook with gas and later on upgrade so that I can save money now. But quickly realized I'll be spending a lot more money overall, so I better start with good stuff from the start and have a better system.

I'm not going to have a microwave, coffee maker, or any other AC appliances, simply because I won't have space for it. I'm a photographer, web developer, designer, so I'll have a lot of camera gear, computer, hard drives, etc, those are my priorities and I already found solutions to charge all of those with DC USB PD chargers.

As long as I have a couple of pots and pans I can cook everything I need, I don't require coffee to function 😅 and the occasional espresso made with a moka pot is plenty for me.

Although I get your point, these are what I think my needs will be right now, after a year on the road many things will change, and overestimating should be the way to go. At the same time, I'm trying to build a truck camper that has decent offroad ability, so I need to find the right balance between minimalism and comfort (which is very difficult). If I'm limited by power I won't be getting any unnecessary appliances that will weigh me down.

Still, if I build a 24V system I already have some overhead there.
 

alfaeric

Solar Enthusiast
I'm building a new truck camper with the purpose of traveling around the world. I know LPG is common in Europe but if I want to go with the fiberglass lighter containers those are not as common and I still have to search for it everytime, which means I need to have 2 for redundancy and those takes a lot of space and weight. Also traveling around and sleeping close it LPG everyday is probably not the safest thing.
On the other hand I did consider saving money and go with that at first and upgrade when needed. If I don't need electricity to cook, half the battery capacity will be enough and a 300W inverter will be more than enough as I will need it only for a PC monitor that draws 25W. When the time comes though I'll have to buy a lot of new stuff though, as everything changes to 24V which means I'll have to spend a lot of extra money
We thought the same thing when building our trailer- and kept gas out of it.

But there could be a time where getting power doesn't happen- so you may consider getting a small gas burner that uses one of the tiny bottles to run it. If not used for primary cooking, they will last a very long time- so the increased cost of the small gas containers is very spread out over time and usage.
 

alfaeric

Solar Enthusiast
I didn't quite understand and I'm very interested in this. I know there are a lot of cheap induction cooktops but I want to get a good one, so how can I check for this?

What's a power factor correcting power supplier?

I'm not sure if you're talking about this, but most small households here in Italy have a maximum draw of 3kW, the upgrade to 4.5 has monthly bill costs. A peak 3kW is very easy to reach of course, so some of the Induction cooktops have features to limit the maximum draw, especially on the big 4 zones that go up to 7kW and more. I don't think the limit is applied as an average (having peak and then off) but it should limit the peak otherwise it will trigger the 3kW breaker.

Also, you mention AC to DC, does that mean induction actually works with DC? Does a DC induction cooktop exist? I tried searching but didn't find anything. That would be perfect without having to use the inverter for that big load, and also save a lot of energy due to conversion loss.
Yes, can someone please elaborate more? Especially how to shop for good components. We have thoughts to convert more to "off grid", and getting a good electric cooking device would be pretty key.
 

12VoltInstalls

Solar Addict
use 6 AWG for ~2-3 feet. On 12v you need #00 which is ridiculously expensive and hard to work with
A couple pizzas difference in price is not ridiculous- it’s just more expensive.

For his intermittent high demand cooking, he’s at the upper echelon for 12V for cooking imho.
But why add 24V-12V conversion for his stated bulk of the time use? One more point of failure.

Nothing wrong with 24v but the argument against 12V doesn’t hit all the “practical” points very firmly in his case imho.
For me if it’s 24V vs 12V I lean 12V: if I’m traveling somewhere and have a failure what’s most likely going to be available ‘locally’ to cob up a temporary solution if something fails? I can’t speak for Europe but stateside 12V is still there.

As far as the comment on Giandel pure sine inverters: clone? Maybe. Some complaints, yes. By and large customer service is applauded, and for inexpensive inverters? Plenty of good reports on it so in that price range it’s not that risky. I for one have been using a 1200W daily for 3-1/2 years +.
 

12VoltInstalls

Solar Addict
traveling around and sleeping close it LPG everyday is probably not the safest thing.
Driving isn’t the safest thing :)

As fuels go, LPG is pretty safe. It’s not like natural gas that can ignite at any concentration and you can turn off the tank when not in use. Just a thought !
 

filippomasoni

New Member
We thought the same thing when building our trailer- and kept gas out of it.

But there could be a time where getting power doesn't happen- so you may consider getting a small gas burner that uses one of the tiny bottles to run it. If not used for primary cooking, they will last a very long time- so the increased cost of the small gas containers is very spread out over time and usage.
Of course, I have a camping stove (with canisters) that I currently use for car camping that I'll bring as a spare or to cook outside.

A couple pizzas difference in price is not ridiculous- it’s just more expensive.

For his intermittent high demand cooking, he’s at the upper echelon for 12V for cooking imho.
But why add 24V-12V conversion for his stated bulk of the time use? One more point of failure.

Nothing wrong with 24v but the argument against 12V doesn’t hit all the “practical” points very firmly in his case imho.
For me if it’s 24V vs 12V I lean 12V: if I’m traveling somewhere and have a failure what’s most likely going to be available ‘locally’ to cob up a temporary solution if something fails? I can’t speak for Europe but stateside 12V is still there.

As far as the comment on Giandel pure sine inverters: clone? Maybe. Some complaints, yes. By and large customer service is applauded, and for inexpensive inverters? Plenty of good reports on it so in that price range it’s not that risky. I for one have been using a 1200W daily for 3-1/2 years +.
Thank you, I was looking for both sides, which will make decisions more difficult, but we are here to discuss and learn from each other right?
In the case of a 24V system, most of the appliances will be 24V, like the fridge (Vitrifrigo, which I believe works on both 12/24) the heater (either Webasto or Eberspacher), water pumps, and USB stuff. The 24-12 converter will be needed mostly for lights and fans I believe.

The point you are making is important though. 24V appliances are available online in Europe easily, but probably not the same in the US, not sure about South America, Africa, or Australia. With a 12V system, I'm more likely to find spare parts everywhere and that's an important point that might render the 400 euro of difference worth it in case of a failure. And I would probably need to carry fewer spare parts.
 

RCinFLA

Photon Sorcerer
Some inverters are better at dealing with this PF aspect - some really struggle.
Simple one-way inverters are more vunerable to damage due to poor power factor loads.

Inverters, generators, and transformers are really rated for VA, not watts. At load PF =1.0 the two being equal.

Since losses goes as I^2 * R, the higher peak currents for poor PF to supply average power with short bursts increases losses. This is common to both simple one-way and hybrid bi-directional inverters.

I believe EU standard EN61000-3-2 requires any appliance that draws greater then 75 watts to have good power factor. This is why you see computer power supplies now having PF correction circuitry. CFL and LED light bulbs can sneak in below regulation power limit. Of course, any EU regulation is not that simple with many other conditions like frequency harmonic content and line noise.
 
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filippomasoni

New Member
Simple one-way inverters are more vunerable to damage due to poor power factor loads.

Inverters, generators, and transformers are really rated for VA, not watts. At load PF =1.0 the two are equal.

Since losses goes as I^2 * R, the higher peak currents for poor PF to supply average power with short bursts increases losses. This is common to both simple one-way and hybrid bi-directional inverters.

I believe EU standard EN61000-3-2 requires any appliance that draws greater then 75 watts to have good power factor. This is why you see computer power supplies now having PF correction circuitry. CFL and LED light bulbs can sneak in below regulation power limit. Of course, any EU regulation is not that simple with many other conditions like frequency harmonic content and line noise.
Thanks for the explanation.
Just to clarify, we need to check that the AC appliance we want to use in our system has a PF correction circuitry. Seems like with that EU standard any reputable induction cooker company needs to have that, and I could check directly with them.
 

BobR

Solar Enthusiast
Hello,
I'm designing the electrical system for a truck camper I'm going to build in the future and I'd like to order the 280ah cells since delivery time is about 3 months from China to Italy.

I need to decide between a 24V and 12V system.

Setup idea:
Solar 600W
Battery: 6720Wh 280ah 24V or 560ah 12V
Daily energy consumption: 2500Wh (worst-case scenario, I estimated 900Wh for cooking and 8h of computer use)

Since I would like to have an induction cooktop I was planning on having a big inverter and so I was decided on 24V, but I recently found a few models of cooktop that can set a maximum power draw of 1600W, 2000W, or 3600W and I'm certain 1600W will be enough for me for 2 zones. So I'll go for a smaller Giandel 2000W inverter.
At this point does it still make sense to have a 24V system or I could go with the simpler 12V?

The truck is 12V and sourcing 12V components will be easier around the world.
The cost will be a bit higher for the 12V, I'll spend more for the MPPT and a bit less for the DC-DC charger and inverter. How I planned the layout I'll have everything electrical close by with less than 1m of cables, except lights and fans, so the only longer cables are going to be for the panels and alternator.

What are your thoughts?

Also unrelated do you know where to source flexible solar panels in Europe? I was going to go with GWL but they recently discontinued their 300W version.
Have you looked into DC powered induction cookers? Induction cookers convert AC into DC and then into high frequency AC.
 

filippomasoni

New Member
Have you looked into DC powered induction cookers? Induction cookers convert AC into DC and then into high frequency AC.
I've tried searching but didn't find anything. Only a few products from alibaba or banggood with poorly written titles pop up.

That would be the perfect solution, if you know of anything please let me know.
 
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